This may be an Access2007 issue, but I don't think so.
There seems to be a lot of terms used by the Original Poster(OP) as if they were interchangable. They are not.
Table - Set of similar records stored as fields
Form - Window to a table (or query) that presents the data from the table in a human-readable display
Control - One element of a form. May contain data from a table, from another source, or no data at all.
Tables can be related, but forms cannot. The perceived relationship between forms is not recognized by Access. Yes, there are wizards to look at the table relationships and construct WHERE clauses (filters) to limit the set of records that are available to a form. Once the wizard is done, the relationships are artificial. If changed incorrectly, Access presents the incorrect data.
Controls are the items on a form. They may be text boxes (textbox or label), yes/no (check boxes, radio buttons, or toggle buttons), buttons, and images. They may contain a single data item, either from the table (bound) or not (unbound). Some controls allow display of multiple items of data as a list or matrix. Listboxes, comboboxes, and subforms are examples.
To want to "Maximize" a control makes no sense. What would a form look like if the "Exit" command button were "Maximized"? For one thing, the form would be useless because there could not be any other controls visible. It would be impossible to reverse this "Maximize" because there could be no "Normal Size" button.
I suspect that what is searched for here is a form to display only the data somehow related to the data displayed in the main form. This would necessitate understanding Modal and Popup as well as Maximize and Normal to control this form (actually 6 forms). How the user is to Maximize this form is also a function of the properties of the form, whether the Maximize/Normal toggle is displayed in the upper-right corner with the Close button, etc.
OP needs to understand these issues. If she already does, then she needs to present the problem without the ambiguity currently present.